By Erik J. Martin, CTW Features
If the word “grub” makes you hungry, you might lose your appetite after learning its alternate definition. Because the type of grub found beneath the grass is not only ugly but also insidious – with the potential to cause widespread damage to your lawn if left unchecked.
Notice turf areas with yellow or brown patches that don’t respond to watering. Finding grass spots that can be easily pulled up? Observing more birds, raccoons and other critters pecking through and digging up the lawn in search of edibles? If so, the odds are high that you have a grub problem.
“Grubs are the larval stage of beetles that reside beneath the surface of lawns, feeding on grassroots and organic matter,” explains Zahid Adnan, a professional gardener and chief editor/founder of ThePlantBible.com. “Female beetles lay eggs in the soil during late spring to early summer, which hatch into grubs in a few weeks. Grubs can infiltrate lawns when eggs are laid on the grass and the larvae burrow into the soil.”
Grubs can wreak havoc on lawns by feeding on grassroots, disrupting the nutrient supply and water absorption of the turf. This results in patches of brown, drying grass that can be easily lifted like a carpet. Grub-infested lawns are also more vulnerable to stress from drought, weed invasion, and other lawn diseases.
“Resolving a grub problem promptly is essential because it can cause severe harm to lawns. If left untreated, grubs can destroy large areas of grass, leading to a weakened and unsightly lawn,” cautions Benita Middleton, had gardener at Benita’s Garden Services.
To confirm the presence of grubs, try this simple test: select a brown patch and lift a section of the turf carefully. Inspect the soil and grassroots, looking for white, C-shaped larvae, which range from a few centimeters to an inch in length.
“If you find more than five to 10 grubs per square foot, it indicates a significant infestation,” adds Adnan.
There are two main ways to eradicate grubs from your lawn: chemical treatments, or chemical-free treatments.
The former involves applying an insecticide product (found at gardening or home improvement stores) containing neonicotinoids or trichlorfon, which can be highly effective in killing grubs. This product is typically applied in late summer or early fall when grubs are small and actively feeding closer to the surface. However, this type of treatment can hurt the environment and may cause potential harm to beneficial insects in your lawn.
Alternatively, you can pursue chemical-free methods, including using nematodes (beneficial microscopic worms) or applying milky spore – a bacterial powder that affects grub larvae. But note that naturalistic treatments could require multiple applications and take much longer to eliminate grubs fully. It’s best to apply nematodes or milky spores in spring or early summer to target newly hatched grubs.
“The recovery time after grub treatment will depend on the infestation severity, the health of the lawn and post-treatment care,” says Aaditya Bhatta, CEO/founder of Plants Craze. “Your lawn may take several weeks or months to fully recover, and additional care may be necessary to promote healthy regrowth.”
Adnan warns that it may actually take an additional growing season for your lawn to fully bounce back.
“Overseeding thin or damaged areas can help your lawn recover more quickly,” continues Adnan.
If you are unsure about the best course of action, it’s best to consult with a professional lawn care service, gardener or horticulturalist who can devise a treatment option tailored to your particular problem and your lawn’s needs.
Once the grubs are gone, don’t get overconfident: They could come back in the future.
“Regular lawn maintenance practices, such as proper mowing height and soil aeration, can help prevent future grub infestations,” Bhatta advises.